Many kinematics also point out that it is best not to stay in the water for too long, otherwise it will damage your health. Swimming time should be controlled at one and a half hours to two hours, and athletes' training is generally only about two hours. This is because people in the water will automatically adjust their body temperature because of the difference with the water temperature. At first, it was ok to collect people's heat. Later, once the heat is not enough, the human body will automatically open protective measures and the blood vessels will contract. This time is not suitable for staying in the water!
This is why our skin turns pale when we first enter the water. After swimming in the water for a period of time, blood circulation is accelerated, blood vessels are opened, heat is increased, and the skin turns from white to red. Then after a while, our heat supply was insufficient, our blood vessels contracted, and our skin turned from red to white!
Not only will our skin change, but if we stay in the water for too long, the heat generated by our bodies will be lower than the heat emitted in the water, and the body temperature regulation function will be destroyed, thus causing arterial contraction and venule expansion, and blood will stagnate in the subcutaneous vein. The skin is not only white, but also blue and purple, blood vessels will contract extremely, and even spasm will occur. If this happens, you must hurry ashore to exercise or wear clothes to keep warm to prevent colds!
Finally, we should remind friends who are weak that if they stay in the water for a little longer, they should go ashore for exercise in time when menstruation comes to avoid cramps, drowning and other accidents. Therefore, you should be more self-disciplined when exercising, and don't do harm to your body because you are playful or greedy, or even cause accidents because you are too playful and soaked in water!